Abstract
“Underwater” endoscopic techniques have gained traction given its potential advantages. The aim of this multicenter randomized trial was to compare the effect of saline immersion (U-POEM) vs. carbon dioxide insufflation during peroral endoscopic myotomy (CO2-POEM) on post-procedural pain.
Consecutive patients with achalasia subtype I and II were randomized in a 1:1 ratio to U-POEM or CO2-POEM during the study period between February 2025 to November 2025. Pain was assessed using the validated numeric pain rating (NPRS) on a scale of 0 (none) to 10 (most severe). Primary outcome was immediate post-procedure pain. Secondary outcomes included: post-procedure pain at different time periods, requirement of analgesics, and clinical response (defined as a post-POEM Eckardt score <3).
Thirty-six patients were randomized to U-POEM (n=18) and CO2-POEM (n=18). Technical and clinical success were 100% in both groups with no immediate and delayed adverse events. There were no differences in dissection speed or procedural time between the two groups. The immediate post-POEM mean NPRS score was significantly lower in the U-POEM vs. CO2-POEM group (1.6 ± 1.6 vs. 3.3 ± 2.6; 95% CI: 0.23-3.16; p=0.02). When compared to CO2-POEM, patients who underwent U-POEM reported less moderate-severe pain (16.7% vs. 55.5%; 95% CI: 0.04-0.64; p=0.04) and a lower number required opioids for post-operative pain management (5.5% vs. 50%; 95% CI: 0.11-0.68; p=0.007). Mean NPRS score remained lower in the U-POEM vs. CO2-POEM group at 72-hours after the procedure (1.13±1.36 vs. 2.26±1.78; 95% CI: 0.06-2.20; p=0.04).
U-POEM was safe, effective, and associated with lower post-procedure pain scores when compared to CO2-POEM (U-POEM trial:NCT06918730).